Radar detector for pre-impact airbag triggering

Abstract

A pulsed radar detector to be used for airbag triggering prior to a collision between a vehicle on a roadway and an impacting target object, has sets of transmitters and receiver separately disposed on a the side of a vehicle so as to create a bistatic antenna pattern. The transmitting antennae are mounted relative to receiving antennae so as to control the amount of direct radiation from each transmitter antenna and said receiver antenna so as to create a modulation of a received target signal. A signal processor determines the period of the modulation in order to obtain a measure of target velocity. The amplitude of the modulation is determined so as to have a measure of relative target size. Using this data, a computer continuous calculates the predicted time and point of impact in order to initiate release of an airbag at a predetermined time before impact between said object and the side of said vehicle.

I claim: 
     
       1. A radar detector for airbag triggering prior to a collision between a vehicle on a roadway and an impacting target object, comprising: at least one set of transmitting and receiving antenna means, each said transmitting antenna being longitudinally spaced apart from said receiving antenna means, wherein each said transmitting antenna is mounted to one side of a transverse centerline passing approximately orthogonal through the longitudinal axis of said vehicle and each said receiving antenna is mounted to the opposite side of said transverse centerline;   mounting means for adjustable support of each said transmitter antenna means and said receiver antenna means so as to provide a uniform bistatic antenna pattern coverage of one or more sides of said vehicle;   at least one set of transmitter and receiver means, each said transmitter means being electrically connected to a respective transmitting antenna, and each said receiver means being electrically connected to a respective receiving antenna;   means for detection of a signal out of said receiver means, said signal resulting from radiation from said transmitter antenna being reflected from an object adjacent the side of said vehicle;   signal processing means for continuous tracking of the position of said target object relative to the side of said vehicle;   computer means for continuous calculation of the predicted time and point of impact, and   means for controlling initiation of an airbag at a predetermined time before impact between said object and the side of said vehicle.   
     
     
       2. A radar detector for airbag triggering prior to a collision between a vehicle on a roadway and an impacting target object, as recited in claim 1, wherein said signal processing means further provides means for determination of target amplitude. 
     
     
       3. A radar detector for airbag triggering prior to a collision between a vehicle on a roadway and an impacting target object, as recited in claim 2, wherein said signal processing means further provides means for continuous tracking of the acceleration of said target object relative to the side of said vehicle. 
     
     
       4. A radar detector for airbag triggering prior to a collision between a vehicle on a roadway and an impacting target object, as recited in claim 3, wherein said signal processing means further provides means for continuous tracking of the velocity of said target object relative to the side of said vehicle. 
     
     
       5. A radar detector for airbag triggering prior to a collision between a vehicle on a roadway and an impacting target object, as recited in claim 4, wherein said detection means includes means for detecting the period of the modulation of the target signal by the direct signal radiation between said transmitter and associated receiver, so as to obtain an estimate of target velocity. 
     
     
       6. A radar detector for airbag triggering prior to a collision between a vehicle on a roadway and an impacting target object, as recited in claim 5, wherein said detection means includes means for detecting the amplitude of the modulation of the target signal by the direct signal radiation between said transmitter and associated receiver, so as to obtain an estimate of target radar cross section. 
     
     
       7. A radar detector for airbag triggering prior to a collision between a vehicle on a roadway and an impacting target object, as recited in claim 4, wherein said detection means includes means for momentarily disturbing the target track at non-critical ranges while varying the detection gain so as to obtain an estimate of target radar cross-section. 
     
     
       8. A radar detector for airbag triggering prior to a collision between a vehicle on a roadway and an impacting target object, as recited in claim 4, further comprising means for continuous direct measurement of the velocity of said object relative to the side of said vehicle. 
     
     
       9. A radar detector for airbag triggering prior to a collision between a vehicle on a roadway and an impacting target object, as recited in claim 8, wherein said means for continuous direct measurement of the velocity of said object relative to the side of said vehicle comprises a doppler radar. 
     
     
       10. A radar detector for airbag triggering prior to a collision between a vehicle on a roadway and an impacting target object, as recited in claim 8, wherein said computing means is a microprocessor. 
     
     
       11. A method of radar detection for airbag triggering prior to a collision between a vehicle on a roadway and an impacting target object, comprising the steps of: providing at least one set of transmitting and receiving antenna means, each said transmitting antenna being longitudinally spaced apart from said receiving antenna means, wherein each said transmitting antenna is mounted to one side of a transverse centerline passing approximately orthogonal through the longitudinal axis of said vehicle and each said receiving antenna is mounted to the opposite side of said transverse centerline;   mounting said transmitter and receiver antenna means with adjustable support means so as to provide a uniform bistatic antenna pattern coverage of one or more sides of said vehicle;   connecting at least one set of transmitter means to a respective transmitting antenna and at least one set of receiver means to a respective receiving antenna;   detecting a signal out of said receiver means, said signal resulting from radiation from said transmitter antenna being reflected from an object adjacent the side of said vehicle;   processing the signal for continuous tracking of the position of said target object relative to the side of said vehicle;   calculating the predicted time and point of impact continuously by computer means; and   controlling the initiation of an airbag at a predetermined time before impact between said object and the side of said vehicle.   
     
     
       12. A method of radar detection for airbag triggering prior to a collision between a vehicle on a roadway and an impacting target object, as recited in claim 11, further comprising the steps of: locating said transmitting and associated receiving antennas relative to each other so as to approximately maintain the received direct signal radiation from said transmitter antenna approximately above the minimum detectable receiver signal level and below the minimum detectable target level; and   detecting the amplitude of the modulation of the target signal by direct signal radiation between said transmitter and associated receiver, so as to obtain an estimate of target radar cross-section.   
     
     
       13. A method of radar detection for airbag triggering prior to a collision between a vehicle on a roadway and an impacting target object, as recited in claim 12, further comprising the steps of: detecting the period of the modulation of the target signal by the direct signal radiation between said transmitter and associated receiver, so as to obtain an estimate of target velocity.   
     
     
       14. A method of radar detection for airbag triggering prior to a collision between a vehicle on a roadway and an impacting target object, as recited in claim 12, further comprising the steps of: disturbing the target track at non-critical ranges momentarily while varying the detection gain so as to obtain an estimate of target velocity.   
     
     
       15. A method of radar detection for airbag triggering prior to a collision between a vehicle on a roadway and an impacting target object, as recited in claim 12, further comprising the steps of: measuring the velocity of said object relative to the side of said vehicle by continuous direct measurement means.   
     
     
       16. A method of radar detection for airbag triggering prior to a collision between a vehicle on a roadway and an impacting target object, as recited in claim 15, wherein said steps of direct measurement of the velocity of said object relative to the side of said vehicle comprises a doppler radar.